LONDON, Oct 14 (Reuters) - A Banksy picture which was half sliced by a shredder concealed in its frame when it was sold at auction fetched 18.6 million pounds ($25.4 million) when it went back under the hammer in the same room in London on Thursday. Onlookers gasped when the then-titled "Girl with Balloon" was sucked into a shredder as the hammer fell following a bid of 1,042,000 pounds at an October 2018 auction at Sotheby"s in London. "Some people think it didn"t really shred. It did. Some people think the auction house was in on it, they weren"t," the street artist, whose identity is a closely guarded secret, said on Instagram in 2018. Now called "Love is in the Bin", the work sold for 18,582,000 pounds, more than three times the top end of its 4-6 million pound price estimate and an auction record for the artist. "I can"t tell you how terrified I am to bring down this hammer," joked Sotheby"s auctioneer Oliver Barker after 10 minutes of bidding. Sotheby"s said the work fitted into an illustrious history of anti-art including Marcel Duchamp"s anonymous submission of Fountain, a porcelain urinal remounted on a pedestal in 1917, to Ai Weiwei, who photographed himself intentionally dropping an alleged Han Dynasty urn. "When Girl with Balloon "self-destructed" in our saleroom, Banksy sparked a global sensation that has since become a cultural phenomenon," said Alex Branczik, Sotheby"s chairman of modern and contemporary art. "During that memorable night, Banksy did not so much destroy an artwork by shredding it, but instead created one. Today this piece is considered heir to a venerated legacy of anti-establishment art." ($1 = 0.7310 pounds)